The present invention relates to a connection clamp that is especially suited for use for handlebar and front mounting units of bicycles. The use of handlebar and front mounting units in bicycles is not the sole possible use, however; connection clamps of the type described here can also be used for instance on vehicles and equipment that have a handlebar or the like for changing direction. For the sake of simplification, the invention will be described below with reference to its use in handlebar and front mounting units of bicycles, but this description should not in any way be understood to restrict its use.
Depending on the type of bicycle and on the field of use of the bicycle, the handlebar can take different forms, but its cross section is usually cylindrical. The handlebar of a bicycle is usually fastened directly onto the front mounting. The fastening is done via a screw clamp. To enable adjusting the length and/or height of the handlebar, the handlebar can be connected to the front mounting by means of connection clamps. Typically two connection clamps, one on the left and one on the right of the front mounting, connect the front mounting to the handlebar. This is then called a handlebar and front mounting unit. Typically, the handlebars, connection clamps and front mountings are manufactured from metal, lightweight metal, or fiber-reinforced plastic.
In the prior art, connection clamps have become known that each have one clamping point on the handlebar and one clamping point on the front mounting. The clamping points are each provided with a clamping slot and a clamping screw.
Also known in the prior art are connection clamps that have only one common clamping point, one common clamping slot, and one common central clamping screw.
A disadvantage of the connection clamps with two clamping points that are known in the prior art is that adjusting the height and/or length of the handlebar is then possible only if all the clamping screws of the clamping points are loosened and then tightened again. This means that it is inconvenient and time-consuming to adjust the height and/or length of the handlebar. Furthermore, connection clamps with two clamping points and two clamping screws are necessarily heavier, because of their design, than connection clamps with only one common clamping point.
A disadvantage of the connection clamps, known in the prior art, that have one common clamping point, one common clamping slot, and one common central clamping screw is that jointly clamping the handlebar, connection clamp and front mounting is possible only if the various clamping points have no tolerances. Experiments have demonstrated that even if there are only minimal tolerances between the handlebar, the connection clamp or the front mounting, it is no longer possible to clamp them securely and without relative rotation.
It is therefore the object of the present invention to make a connection clamp available that meets the demands described above and that in particular assures reliable function while being easy to adjust.
This object is attained according to the invention by the subject of claim 1.
The present invention has made a connection clamp available that has high functional reliability and makes easy adjustment possible.
A connection clamp of the invention has one bore for clamping the handlebar and one bore for clamping the front mounting. Each of the two bores has its own clamping slot. The two clamping slots are substantially parallel to one another, and the clamping slots penetrate the bores toward their center axis.
The two clamping slots are actuated with only a single clamping screw. The clamping screw is located parallel to the clamping bores.
The two clamping slots can be positioned in at least a first opening position and in a second clamping position. The width of the two clamping slots in the opening position is greater than the slot width in the clamping position.
The connection clamp of the invention has many advantages.
One particular advantage of the connection clamp is that the two clamping bores with only a single clamping screw clamp completely independently of one another, and that the clamping screw is located outside the path of force.
In experiments it has been shown that even at relatively great tolerances between the handlebar, connection clamps and/or front mounting, the two clamping slots of the clamping bores already decrease in size at only a slight tightening moment of the clamping screws, such that reliable clamping is attained. Because only one clamping screw is used, the installation time can be shortened and the weight reduced in the connection clamp of the invention.
Another advantage of the connection clamp of the invention is enhanced safety in use, since because only one clamping screw is used, there is less risk that a clamping screw might fail to be tightened. Yet the advantages of the connection clamp having two clamping screws, that is, completely independent clamping points, are preserved.
In a preferred refinement of the invention, the fastener is a screw device with a screw as the tensioning element, and the screw preferably has a screw head with a hexagonal socket. However, it is also possible for the fastener to be provided with a fast-tightening device, for instance via an element of the kind used in so-called fast-action hubs in the bicycle field.
In a further preferred refinement of the present invention, an extension is provided on at least one side of the clamping bore of the handlebar. The connection clamp can be mounted with the extension pointing outward or inward.
If mounted pointing outward, this extension reduces the notch tension between the handlebar and the connection clamp. If pointing inward, this extension has a stiffening effect on the handlebar.
The extension can also be embodied outward and inward, and then both advantages are jointly effective.
In a further preferred refinement of the invention, the connection clamp substantially comprises a solid material and is at least in part of a metal or plastic. To reduce weight, lightweight metal, and especially preferably aluminum, or an aluminum or titanium alloy, is preferably used. As the material, a fiber-reinforced plastic can also be used, for example.
In a further preferred refinement of all the versions described thus far, recesses are made from the side of the clamping screw, in order to reduce the weight. These locations are especially suitable, since experiments have shown that no force transmission occurs there, and these recesses have no influence whatever on the service life and durability of the connection clamps.